Differences in activity between reproductive and non-reproductive freshwater turtles during the nesting season

Variation in responses to environmental heterogeneity impacts individual fitness. Freshwater turtles, for example, may modify their behaviour during the reproductive season, depending on their sex or reproductive status. We used accelerometers to track fine-scale activity and assess behavioural differences between males, gravid females, and non-gravid females in free-ranging Blanding’s turtles and Painted turtles during their nesting season (June). There were differences in activity between gravid females on the one hand, and males and non-gravid females on the other hand during the nesting season. Gravid females spent more time sitting and walking, and less time underwater compared to non-gravid females and males. We did not find activity differences between males and non-gravid females, nor between the two species. The differences in movement of gravid females suggest that variation in freshwater turtle activity is largely driven by reproduction, for instance prolonged periods of walking in search of nest sites. These differences in activity may lead to differential mortality risk between sexes in turtle populations. Thus, understanding movement dynamics is crucial not only to expand our knowledge of animal ecology, but is also to improve success of conservation strategies.